Diffei Academic丨mNGS effectively identifies arteriovenous blood pathogens in patients with left-sided infective endocarditis

Introduction

In December 2023, the cardiac surgery team of Guangdong Provincial People's Hospital cooperated with Difei Medical toClinica chimica acta(IF=5.0)The magazine published a research paper.The article included 79 patients with left-sided infective endocarditis (LSIE) after valve surgery for a prospective study.The patient's venous blood, arterial blood and valve samples were collected for culture and mNGS detection.The purpose is to explore the detection performance, influencing factors and bacterial flora distribution of mNGS in venous and arterial blood of patients with LSIE, and to provide favorable basis for the clinical application of mNGS.

Research Background

Infective endocarditis (IE) is an infection that occurs on natural or artificial heart valves, endocardial surfaces, or implanted cardiac devices.The incidence of early cardiac surgery is 50%, and mortality within one year is 30%.The 2015 European Society of Cardiology (ESC) guidelines on IE point out that positive blood culture is an important cornerstone of its etiological diagnosis.

However, the use of specific bacteria, fungi, or antibiotics results in pathogens that are often undetectable by traditional diagnostic methods, resulting in a large proportion of IE cases with blood culture-negative infective endocarditis, thus delaying the treatment of these patients.Therefore, rapid and reliable diagnostic methods are crucial for timely identification of potential causes and personalized management of the disease.

Research methods

The study finally included 79 patients with left-sided infective endocarditis who underwent valve surgery in the hospital. Their venous blood, arterial blood and valve samples were collected, and blood culture, valve culture, venous blood mNGS and arterial blood mNGS were tested respectively.

Figure 1 Flowchart of the study

Research result

Evaluation of six different mNGS- and culture-based IE detection methods

The study evaluated and compared the performance of six IE diagnostic methods, including blood culture, valve culture, venous blood mNGS, venous blood mNGS + blood culture, arterial blood mNGS and arterial blood mNGS + blood culture.The results showed that blood culture was significantly better than valve culture in detecting pathogens (P=0.046; Figure 2), while the positive detection rates of venous blood mNGS and arterial blood mNGS were 43.0% and 49.4% respectively, which were significantly higher than blood culture (32.9%) and valve culture (19.0%) (Figure 2).

In addition, whether it is venous blood mNGS or arterial blood mNGS, the positive detection rate of combined blood culture is higher than that of a single test, indicating that combined blood mNGS based on conventional culture methods has potential diagnostic value for detecting pathogens in LSIE patients.

Figure 2 Diagnostic performance of different detection methods for LSIE patients

Compare different blood mNGS methods and evaluate factors affecting mNGS detection capabilities

The study explored the performance of different blood mNGS methods and found that the positive rate of arterial blood mNGS was higher than the positive rate of venous blood mNGS (Figure 2), but the difference was not statistically significant (P=0.425).The combined use of venous blood mNGS and arterial blood mNGS results cannot significantly increase the positive detection rate (P = 0.215).Twenty-three different clinical characteristics were evaluated using univariate analysis to further analyze factors that may influence the ability of mNGS to detect IE.The results showed that preoperative white blood cells (P = 0.027), neutrophils (P = 0.018), vegetation larger than 14 mm (P = 0.043), aortic valve vegetation (P = 0.048) and mNGS detection results are statistically significant.

Microbiome analysis

An analysis of the distribution of bacterial flora in the plasma of 79 LSIE patients found that venous blood mNGS detected a total of 38 pathogenic bacteria and 4 cases of mixed infection; arterial blood mNGS detected a total of 43 pathogenic bacteria and 3 cases of mixed infection.Among them, the common pathogenic bacteria in venous blood samples were 5 strains of oral Streptococcus, 3 strains of Streptococcus sanguinis, 4 strains of Acinetobacter haemolyticus, and 5 strains of Bartonella five-day fever; while the common pathogenic bacteria in arterial blood were 8 strains of oral Streptococcus, 8 strains of blood There were 3 strains of Streptococcus, 4 strains of Acinetobacter haemolyticus, and 6 strains of Bartonella five-day fever.

Comparing blood culture and mNGS, both methods were effective in detecting streptococcal infection (Figure 3B).Blood cultures appeared to have a greater ability to detect cocci strains other than Streptococcus and were not detectable for any of the gram-negative bacteria, fungi, or Bartonella quintessense identified by mNGS.

Figure 3 Distribution of pathogens detected by different detection methods in 79 LSIE patients.(A) The number of patients infected by specific pathogens detected by venous blood mNGS and arterial blood mNGS; (B) Microorganisms detected by different detection methods

in conclusion

mNGSIt is a promising diagnostic method that can detect free DNA in venous blood or arterial blood of patients with LSIE. Combining blood-based mNGS with blood culture can effectively identify pathogenic microorganisms, thereby guiding timely clinical diagnosis and treatment. , providing valuable diagnostic information for optimizing antibiotic treatment in high-risk LSIE patients.

references:

Zeng X, Liang Y, Wang H, Chen J, Xu Y, Ou Q, Yin J, Zhuang J, Xiong W, Tang L, Li X, Tong G, Lei L, Jian X. Detection of pathogens from venous or arterial blood of patients with left-sided infective endocarditis by metagenomic next-generation sequencing: A prospective study. Clin Chim Acta. 2024 Jan 1;552:117698. doi: 10.1016/j.cca.2023.117698. Epub 2023 Dec 10. PMID: 38072301.

Compiler: Xue Leng Review: Jia Typesetting: Lin